Article ID: 2026-0255
Background: Preoperative sarcopenia and impaired muscle status are increasingly studied as markers of biological vulnerability in spine surgery. Interpretation remains difficult because studies use heterogeneous assessment strategies, including formal clinical definitions, isolated muscle mass proxies, and muscle quality measures.
Methods: This systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020. The original search was conducted on April 8, 2026, and was updated on April 12, 2026, across MEDLINE/PubMed, Embase, Scopus, Web of Science, BVS, and SciELO. After peer review, the strategy was expanded and rerun to improve sensitivity for muscle quality and paraspinal degeneration terms. Adult spine surgery studies reporting preoperative sarcopenia or muscle-related measures and postoperative clinical, functional, mechanical, or survival outcomes were eligible. Studies were classified as clinical sarcopenia, muscle mass proxy, or muscle quality according to the dominant exposure definition. Methodological quality was assessed using the Newcastle-Ottawa Scale, and findings were synthesized narratively because of substantial heterogeneity.
Results: The expanded search rerun yielded 10,350 exported records from PubMed/MEDLINE, Embase, Scopus, Web of Science, and BVS. After deduplication, 4,831 unique records remained; all 49 originally included studies were recovered by digital object identifier. Title/abstract screening excluded 4,616 records, leaving 215 reports for eligibility assessment: 84 original eligibility reports and 131 newly retrieved reports from the expanded rerun. Twenty-seven additional eligible studies were identified, resulting in 76 included studies. Twelve studies used clinical sarcopenia definitions, 32 used muscle mass proxies, and 32 used muscle quality measures. Overall, 60 studies reported an association between sarcopenia or impaired muscle status and worse postoperative outcomes, 11 reported no statistically significant association, and five reported partial or subgroup-dependent findings. Five newly included records were available only as abstracts and were extracted only for information explicitly reported in the abstract.
Conclusions: Preoperative sarcopenia and impaired muscle status appear to be associated with worse outcomes in several spine surgery contexts, but interpretation depends strongly on the assessment strategy, surgical population, outcome domain, and adjustment approach. Clinical sarcopenia may reflect systemic vulnerability, whereas paraspinal muscle quality may be particularly relevant to mechanical and alignment-related outcomes. Given the predominance of observational and heterogeneous evidence, sarcopenia assessment should be considered an adjunctive risk-stratification marker rather than an isolated causal determinant or universal indication for routine implementation.
